The EvStat class

(PECL ev >= 0.2.0)

Introdução

EvStat
monitors a file system path for attribute changes. It calls
stat()
on that path in regular intervals(or when the OS signals it changed) and
sees if it changed compared to the last time, invoking the callback if it
did.

The path does not need to exist: changing from "path exists" to "path does
not exist" is a status change like any other. The condition "path does not
exist" is signified by the
'nlink'
item being 0(returned by
EvStat::attr()
method).

The path must not end in a slash or contain special components such as
'.'
or
..
. The path should be absolute: if it is relative and the working directory
changes, then the behaviour is undefined.

Since there is no portable change notification interface available, the
portable implementation simply calls
stat()
regularly on the path to see if it changed somehow. For this case a
recommended polling interval can be specified. If one specifies a polling
interval of
0.0
(highly recommended) then a suitable, unspecified default value will be
used(which could be expected to be around 5 seconds, although this might
change dynamically).
libev
will also impose a minimum interval which is currently around
0.1
, but that’s usually overkill.

This watcher type is not meant for massive numbers of
EvStat
watchers, as even with OS-supported change notifications, this can be
resource-intensive.